1. Field of the Invention
The present invention relates to a process of electrolytically producing a screen by forming a screen skeleton upon a matrix in a first electrolytic bath, subsequently stripping the formed screen skeleton from the matrix and by subjecting said screen skeleton to an electrolysis in a second electrolytic bath in the presence of at least one brightener.
2. Description of the Prior Art
A process of this type for producing a screen is known in the art. In this known process, a screen skeleton is produced upon a matrix provided with a stripping means such as beeswax, the structure of said matrix corresponding with that of the screen to be produced; the screen skeleton being obtained by a deposit of metal, whereupon the thin skeleton is stripped from the matrix and is finally subjected to an electrolysis in the presence of a brightener, if any. In this process, electrolytic baths are used comprising nickel salts and eventually brighteners of the first class, the molecules of which contain a ##STR2## group, examples of which are e.g. sulfonic acids, mono- and dibasic sulfonic acids, sulfonic acid esters, sulfonamides, sulfonimides, sulfinic acids and sulfones.
A great drawback of said known process is that the dimensions of the lands in the screen skeleton will grow throughout by the nickel deposit, causing said lands to obtain a round cross section, which will give rise to a restriction of the size of the apertures in the screen to be produced, so that the passage of said screens is hampered.